Slot Values and Bonus Pools
The purpose of slot values and bonus pools is to limit the amount of the signing bonuses that drafted players can receive. Every draft pick in the first 10 rounds, plus the supplemental rounds, is assigned a slot value. The higher a player is drafted, the higher the slot value. The slot value is more of a suggestion than a hard number, and teams do have flexibility in determining how much to give to each drafted player as a bonus.
The total slot values for each team amounts to its bonus pool. A teams pool is based on the positions of its picks as well as the amount spent in last years draft. In addition, any amount paid to players drafted in rounds 11-40 above $125,000 are subject to the bonus pool.
If a team exceeds its bonus pool, MLB assess a luxury tax on the excess. For 5% or less, the tax is 75% of the amount above the bonus pool. 5-10% over result in a 100% tax and the loss of next years first round pick.
If a team does not sign a player in the first 10 rounds, the slot value for that player is deducted from the bonus pool. So, a team cant draft a really great prospect and pay him all the money, while ignoring the other picks. If a team signs a player for less than their slot value, the extra money can be used on another pick.
The Mariners have a bonus pool of $6,737,300. The first round pick has a slot value of $3,333,200, the second round pick is $1,206,900. The third round pick is slotted at a paltry $579,800. I know, whats the point of being drafted in the third round?